Evidence for excess argon during high pressure metamorphism in the Dora Maira Massif (western Alps, Italy), using an ultra-violet laser ablation microprobe (super 40)Ar-(super 39)Ar technique
Article Abstract:
The Dora Maira Massif in the western Alps in Italy undergoes high pressure eclogite/amphibolite metamorphism which results in excess argon having high (super 40)Ar-(super 39)Ar ratios, and a relation exists between apparent ages and metamorphic textures. At high pressure conditions, excess argon is formed which, after mixing with atmospheric constituents during fast cooling and retrogression, lead to high argon concentrations and (super 40)Ar/(super 39)Ar ratios. A major portion of the argon ratio is related to high closure temperature minerals or large diffusion domains in single mineral phases.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1995
User Contributions:
Comment about this article or add new information about this topic:
Stable isotope geochemistry and phase equilibria of coesite-bearing whiteschists, Dora Maira Massif, western Alps
Article Abstract:
A study was conducted in Dora Maira Massif, western Alps, to determine temperatures by oxygen isotope thermometry. Accurate data about peak metamorphic pressure, temperature and fluid composition of the whiteschists enables the understanding of the metamorphic processes in the deeper crustal regimes. The intimate and enigmatic connections between the whiteschists and the hosting orthogneiss, the deprivation of the rock's iron content and the enhancement of magnesium content in the whiteschists can be determied from the metasomatism of the orthogneiss protolith by a slab-derived fluid.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1993
User Contributions:
Comment about this article or add new information about this topic:
Ultra-high temperatures from oxygen isotope thermometry of a coesite-sanidine grospydite
Article Abstract:
The oxygen isotope compositions of mineral separates from a ultra-high pressure-temperature coesite-bearing grospydite are measured in order to estimate temperatures of formation. Results show that the oxygen isotope thermometric estimates are the highest measured to date due to the extremely refractory behavior of the grospydite mineral assemblage combined with a rapid cooling from ultra-high temperatures.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1992
User Contributions:
Comment about this article or add new information about this topic:
- Abstracts: Eclogite-facies rocks in the Saxonian Erzgebirge, Germany: high pressure metamorphism under contrasting P - T conditions
- Abstracts: Changes in stable isotope ratios of metapelites and marbles during regional metamorphism, Mount Lofty Ranges, South Australia: implications for crustal scale fluid flow
- Abstracts: Petrology of the Chilliwack batholith, North Cascades, Washington: generation of calc-alkaline granitoids by melting of mafic lower crust with variable water fugacity
- Abstracts: Distribution of trace elements during breakdown of mantle garnet: an examplefrom Zabargad. Distinct site preferences for heavy and light REE in amphibole and the prediction of (super Amph/L)D(sub REE)
- Abstracts: Effects of F, B2, O3 and P2O5 on the solubility of water in haplogranite melts compared to natural silicate melts